Previous studies have demonstrated that sensorimotor processing depends on the behavioral context in which it occurs. In particular, vestibular responses that maintain gaze and posture stability during motion are modulated by context in ways that optimize performance. Although adaptation of vestibular responses has received extensive attention, the neural mechanisms for context-specific vestibular responses are not well understood. I propose to study context-specific vestibular processing in the pigeon, an animal for which a discrete and relevant context (flight) can be simulated in the laboratory. To investigate the effect of context on vestibular processing, I propose two specific aims: (1) To determine the effect of simulated flight context on vestibular head and body stabilization responses to rotational motion; (2) To characterize the effect of simulated flight on neural responses to rotational motion in the brainstem vestibular nuclei. I will compare vestibulospinal responses with the animal at rest and in airflow-evoked flight posture. I will use these behavioral results to inform my electrophysiological recordings in the vestibular nuclei, wherein I will document context-dependent changes in single-unit vestibular responses. In order to understand how impairments in contextual processing may contribute to postural instability and related disorders in humans, we need to have a better understanding of the neural substrates underlying context-dependent modulation of vestibular responses. I propose to use an animal model to study the neural mechanisms for optimization of vestibular responses to a discrete and meaningful context. This study will give us insights into where and how context exerts its effects on the vestibular system. [unreadable] [unreadable] [unreadable] [unreadable]